[Amps] Current thinking on HV supply bleeder current?

[Dr. David Kirkby]

On 02/28/12 08:42 PM, Jim Barber wrote:
>
> I have a 3KV, 2A CCS transformer, and 32uf of filter. What's the current
> state of argument for appropriate bleeder current? The last time this
> came up I seem to remember seeing everything from "HV safety bleed off
> only" up to a rather high number.
>
> So... 100 ohms per DC volt? That would work out to a convenient 400K,
> which could be four 100K in series, each with 1KV or so across them.
>
> Comments?
>
> Thanks,
> Jim N7CXI

My own thinking is that if it drops to 50 V within 30 s then it is OK. I've no 
idea if there's any ISO/IEEE standard for it, but to me 50 V is unlikely to 
cause any problems (although I believe people have been electrocuted with less), 
and 30 s is a reasonable period to wait.

Dropping the voltage to safe levels within 2 s seems to be a bit over the top to 
me. If anyone is using HV supplies, they should know it is would be unwise to 
put ones fingers inside 2 s later.

Obviously, the faster you make it safe, the more power you must dissipate. To me 
at least, 30 s and 50 V are "reasonable" values.

Others will no doubt disagree.

Dave